1. Field of the Invention
The present invention relates to a method for enabling fast editing of a plurality of interrelated files recorded on a rewritable storage medium.
2. Description of the Related Art
Recently, the standardization for new high-density rewritable optical disks capable of recording high-quality video and audio data for a long time is in rapid progress and new optical disk related products are expected to be commercially available on the market in the near future. The Blu-ray Disc Rewritable (BD-RW) is one of the new optical disks.
FIG. 1 illustrates a schematic diagram of a part of an optical disk apparatus such as a video disk recorder (VDR) that records/reproduces data on/from a storage medium like a BD-RW. The optical disk apparatus comprises an optical pickup 2 for reading recorded signals from a storage medium 1 such as a BD-RW or for recording input data on the storage medium 1, a VDR system 3 for processing the signals received from the optical pickup 2 or for converting an input data stream into a data stream formatted for recording, and an encoder 4 for encoding an input analog signal to output the encoded signal to the VDR system 3.
The optical disk apparatus reads play list information stored in a plurality of play list files recorded on the BD-RW 1 and displays the play list information as a selectable menu on a TV screen, as depicted in FIG. 2; therefore, a user may select a play list from the displayed play list information.
The VDR system 3 performs playback or editing of a data stream of the program corresponding to the play list selected as explained above.
FIG. 3 illustrates the file structure of a BD-RW. The root directory contains at least one DVR directory, which contains files such as ‘info.dvr’, ‘menu.tidx’, and ‘mark.tidx’ and subdirectories such as PLAYLIST, CLIPINF, and STREAM. The PLAYLIST directory contains play list files (*.rpls and *.vpls). The CLIPINF directory contains clip information files (*.clpi). The STREAM directory contains MPEG2-formatted A/V stream clip files (*.m2ts) corresponding to the clip information files.
The playback control information for the stream files stored in the STREAM directory, for example, ‘01001.m2ts’ and ‘02000.m2ts’, are stored in the files ‘01001.clpi’ and ‘02000.clpi’ contained in the CLIPINF directory, respectively. The play list information for determining continued playback or playback order of the files ‘01001.m2ts’ and ‘02000.m2ts’ are stored in the file ‘01001.rpls’ contained in the PLAYLIST directory.
Consequently, the clip information files (*.clpi) containing playback control information for the A/V data streams recorded in the data stream files (*.m2ts) and the play list files (*.rpls and *.vpls) are related to each other. When a data stream is recorded as a clip, a play list referencing the clip is created automatically. Such a play list is called a real play list (*.rpls). A user may select partial intervals of recorded clips and create a play list referencing the selected intervals or clips. Such a play list is called a virtual play list (*.vpls).
As depicted in FIG. 4, Clip Info File 1 is referenced by both Real PlayList 1 and Virtual PlayList 1. Real PlayList 1 and Virtual PlayList 1 also reference Clip Info File 2. When deleting a part or the whole of RealPlayList 1 in response to a user's request, the VDR system 3 finds that Real PlayList 1 references Clip Info File 1 and Clip Info File 2 and scans the PLAYLIST directory for the virtual play lists referencing Clip Info File 1 and Clip Info File 2.
By the search operation, the VDR system 3 finds that Virtual PlayList 1 references Clip Info File 1 and Clip Info File 2 and inquires of the user whether to delete Virtual PlayList 1. Responsive to a confirmation for deleting Virtual PlayList 1 from the user, the VDR system 3 performs necessary steps to delete Virtual PlayList 1 and Real PlayList 1 to execute the user's request.
To delete or edit a real play list selected by a user, all the virtual play lists contained in the PLAYLIST directory should be scanned sequentially, which is a time consuming task.
In addition, in the case where a new real play list needs to be added by a user's request or as the result of partially deleting a clip file, the VDR system 3 should examine all play list files and clip information files to determine whether an additional play list may be created without exceeding the limits of the number of play items, the number of entries belonging to the entry point map, and the number of program sequences specified by the recording format of the BD-RW 1. Such a search operation makes editing operations slow.